Higher plants are autotrophic organisms that can synthesize all of their molecular components from inorganic nutrients obtained from the local environment. Nitrogen is a key element in many compounds present in plant cells. It is found in the nucleoside phosphates and amino acids that form the building blocks of nucleic acids and proteins, respectively. Availability of nitrogen for crop plants is an important limiting factor in agricultural production, and the importance of nitrogen is demonstrated by the fact that only oxygen, carbon, and hydrogen are more abundant in higher plant cells. Nitrogen present in the form of ammonia or nitrate is readily absorbed and assimilated by higher plants.
Because of the dependence of plants upon nitrogen, farmers frequently include nitrogen in their fertilization efforts of their fields in an effort to increase yield. This practice may be traced back to the 1800's, when it was discovered that when external sources of water soluble forms of nitrogen (along with phosphorus and potassium) provided to plants, yield increased. These fertilizers are typically applied to the soil, but can also be applied to plant leaves directly.
Nitrogen fertilizers are often synthesized using the Haber-Bosch process, which results in the production of ammonia. The ammonia is then either applied to the soil or used to produce other nitrogen compounds, such as ammonium nitrate or urea. These compounds are then applied to crop fields in order to increase yield in areas where the nitrogen content of the soil is low.
Unfortunately, the production and use of nitrogen fertilizers has significant drawbacks. For example, it is currently estimated that ammonia production accounts for 5% of the global consumption of natural gas. With the increase of natural gas prices over the course of the past decade, the cost of producing ammonia has correspondingly increased. In addition, overuse of nitrogen fertilizer can lead to pest problems by increasing the birth rate, longevity, and overall fitness of certain crop pests. Also, there are substantial concerns regarding fertilizer runoff, which can add undesirable compounds to rivers, streams, and ground water supplies.
It would therefore be desirable to minimize the application of inorganic fertilizers to field crops while finding a way that the increased yield those fertilizers typically provide may still be obtained.
Another source of plant nutrition historically has been humus, which is commonly referred to as organic matter. Humus is sometimes referred to simply mean mature compost, and is often thought to make up the structural component of soil. Most humic compounds are produced via the composting process, but others are available from other sources, such as peat moss, manure, and coal.
Such humic compounds have been used as soil enhancers or fertilizers for quite some time, but the greater benefit seen by artificial application of inorganic compounds such as nitrogen described above have proven more beneficial in most farming applications, or at least more cost effective.
Because of this perceived greater benefit to the application of inorganic nitrogen and other compounds (such as potassium and phosphorus), the level of humic compounds present in the soil has progressively declined with the increase in commercial farming and the lack of replenishment. As a result, greater amounts of inorganic fertilizers are needed in order to achieve the same or similar fertilizing effect, as the soil in many instances is less able to retain the chemical fertilizers applied to it, and as a result plants are less able to utilize such fertilizers unless they are applied in greater quantities. This shift in soil dynamics over the course of time has contributed to the negative impacts of chemical fertilizers noted above, as with increased application of such fertilizers, there is a corresponding increase in the potential for occurrence of the negative side effects of such fertilizers.
While these problems have been recently identified, a suitable solution has yet to be found. Combining various humic substances with various inorganic fertilizing materials, such as nitrogen, phosphorus, and potassium, does result in a somewhat improved fertilizing effect. However, previously used substances have not yet achieved desired results based on the vast numbers of alternative sources of both humic compounds and inorganic complements, as well as the vast number of possible differences in composition and method of preparation. As a result, there has been a need for a compound that is able to deliver both for the benefits of humic compounds and inorganic fertilizers with a high degree of fertilizing efficacy.